. >> tamerlan tsarnaev spend six months in russia. they interviewed him before he left. >> i want to know why after he was interviewed and after a foreign intelligence service raises the flag on the individual why he was allowed to travel abroad. >> some lawmakers insist the fbi did as much as they could. >> at some point, they have nothing. you can't ask them to do something with nothing. >> many questions about where this investigation is headed >>> the fbi is also disputing the mother of the suspect. she says that after the bombing on monday, the fbi came back and interviewed her older son but the fbi says, that's not the case. laura? >> thank you very much for the update, tracy. new details about the wild shootout with police that left one of the bombing suspects dead and the other injured. the watertown police chief telling the boston globe that 26-year-old tamerlan tsarnaev was alive and struggling with officers. the chief says the injuries from that crash are what ultimately killed him. >> in the meantime, federal investigators